This invention relates to floating booms and more particularly to floating containment booms which are used to contain spills of oil and other combustible liquids.
Containment booms are floating barriers which surround an area of water during the transfer of fuels or other combustible liquids. In the event of a fuel spill, the containment boom acts as a floating fence to contain and confine the spilled product to a relatively small area until it can be safely and completely removed. Containment booms thus facilitate cleanup and prevent the spread of the spilled fuel, thereby reducing the risks of danger to personnel and damage to the environment and to other nearby natural and manmade structures.
The "flash point" of a combustible material is the lowest temperature at which the vapor of the material ignites spontaneously in air. Liquids which have a low flash point are typically relatively volatile and tend to vaporize at ambient temperatures and pressures. Low flash point materials are likely to ignite under ambient conditions in the event of a spill and thus present a comparatively greater danger of explosion during transfer. The term "low flash point", as used herein, means those combustible materials having a flash point temperature of less than 100.degree. C.
On the other hand, high flash point liquids are generally less volatile and are less likely to ignite under ambient conditions. High flash point liquids present a comparatively low risk of explosion during transfer or in the event of a spill but, if spilled, the high flash point product remains in and on the surface of the water, with potentially serious consequences to the environment, property and marine life, until it is removed. The term "high flash point", as used herein, means those combustible materials having a flash point temperature of greater than 100.degree. C.
The flash point of a combustible liquid is important in determining whether a containment boom is used during transfer of such liquids. Booms are used (and in some jurisdictions are required) for the transfer of a relatively high flash point, low volatility product. The boom can contain any spills of the high flash point product in a relatively small, confined area until the spill is cleaned up. On the other hand, the transfer of a relatively low flash point, high volatility product preferably occurs in an unboomed area, so that any spills of the low flash point product are free to volatilize and dissipate away from the fuel transfer site. This reduces the risk of ignition and explosion of the spill and of nearby combustible liquids.
When numerous transfers of a variety of combustible liquids are planned, e.g., the filling of fuel tankers, repeated installation and removal of a containment boom around the transfer area becomes labor-intensive, time-consuming and therefore costly. Demurrage of vessels as a result of time delays associated with installation and removal of containment booms and the serial transfer of one product at a time further increases the product costs. Accordingly, careful scheduling and planning are required to minimize "downtime" and cost. Further, serial transfer of combustible liquids between compartmentalized tanks or vessels creates significant and potentially catastrophic mechanical stresses within the empty compartments of a receiving tank or vessel because of concentrated and unbalanced loads during product transfer. The term "vessel", as used herein, means any movable marine vessel, such as a tanker, ship, barge or the like, or any stationary vessel, such as a loading or receiving tank, vessel or the like located on land, or on a dock, pier or other stationary structure.
Containment booms typically comprise individual boom sections or partitions which link interchangeably for ease in installation and removal. Each boom section is normally about one hundred feet long and ends in a boom connector which links another boom section in a relatively liquid-impermeable engagement to prevent the leakage of fluids. After the need for containment is past, the boom sections are disengaged from one another to facilitate their removal, transportation and storage.
Engagement and disengagement of the boom sections generally requires the labor of one or more operators to place and secure the boom sections together in the water. Boom operators thus require transportation to and from the boom site, typically in combustion engine-powered water craft. These craft must stay near the boom if the boom is to be used during the transfer of low flash point materials because there may be an instant need for boom disconnection. However, the presence and operation of such craft in or near the containment area itself creates a risk of explosion of combustible liquids from the engines and thus presents a potential danger to life and property. Further, the labor and time required to install and remove a containment boom during a fuel transfer process increases the time required for transfer and thus the detention of the loading and transferring vessels, and hence increases the ultimate costs of the fuel.
Prior art containment booms include various mechanisms for disconnecting boom sections. For example, U.S. Pat. No. 3,818,708 to Benson discloses a containment boom having hinged sections held together with a removable straight pin which extends vertically through the hinge. U.S. Pat. No. 4,016,726 to Campbell et al. discloses a connector hinge for a containment boom having male and female portions held together with a clevis pin. U.S. Pat. No. 4,295,726 to Campbell et al. discloses a connector hinge for a containment boom having male and female portions held together with a clevis pin. U.S. Pat. No. 4,295,756 to Blair, U.S. Pat. No. 5,190,402 to Vick and U.S. Pat. No. 3,848,417 to Smith et al. each disclose a containment boom connector having interlocking plates held together with a releasable, clevis-type pin. U.S. Pat. No. 4,155,664 to Acheson discloses a containment boom connector having interlocking plates held together with a sliding pivot pin.
None of the described prior art devices permits quick, remote disengagement of the boom sections. Disengagement of the Benson boom connector from a remote location is difficult if not impossible because of the vertical orientation of the pin in the hinge.
It would be advantageous from the perspective of safety and efficiency to provide a containment system which alleviates or eliminates the above-described disadvantages in the transfer of combustible liquids.
It is thus an object of the invention to provide a containment boom which can be easily and quickly installed and removed.
It is a further object of the invention to provide a containment boom which can be easily and quickly disconnected from a remote location.
It is a further object of the invention to facilitate the transfer of combustible liquids by the use of a containment boom which can be easily and quickly disconnected from a remote location.
It is a further object of the invention to provide a method for transferring two or more combustible liquids, including a low flash point liquid, at one time within a boomed area without resetting or removing the boom.
A containment boom according to the present invention includes a boom connector which can be quickly and remotely disconnected. The sections of the boom connector mate in a male-female engagement and include one or more release elements which hold the mating sections together. Remote activation of a release mechanism attached to the release element disengages the release element holding the male and female portions of the boom connector together. The combined action of waves, wind and current causes the disconnected boom sections to drift apart from one another, thereby opening the containment area. The remotely disconnectable boom connector thus permits quick and easy disconnection of a containment boom from a location distant from the boom, such as a pier or transfer vessel. Use of a remotely disconnectable boom connector also permits the simultaneous transfer of both low- and high flash point liquids, because the containment boom can contain the area in the event of a high flash point product spill and yet can be quickly and remotely disconnected in the event of a low flash point product spill.
Accordingly, one embodiment of a remotely disconnectable containment boom includes a first boom section having a female portion of a quick release boom connector affixed thereto and a second boom section having a male portion of a quick release boom connector affixed thereto. The female portion of the connector includes a pair of spaced parallel walls which extend along a first axis. Each of the walls has a channel extending through it perpendicular to the first axis. A transverse member extends between the walls perpendicular to the first axis. An alignment element is mounted externally to one of the walls.
The male portion of the connector has a single wall extending along a second axis and further includes a transverse member engaging element which in operation engages with the transverse member on the female portion of the releasable boom connector. The single wall of the male portion also has a channel extending through it perpendicular to the second axis. When the male and female portions of the releasable boom connector are operatively engaged, i.e., with the single wall of the male portion inserted between the walls of the female portion, the first axis and the second axis overlap and the channels in each of the walls are collinear with the alignment element on one of the walls of the female portion. The quick release boom connector further includes a securing element which can be removably disposed within the channels of the male and female portions of the boom connector to secure them together when they are operatively engaged. The connector further includes a remote activating element attached to the securing element. This remote activating element is used to remove the securing element from the channels in the male and female portions of the connector from a remote location.
Another aspect of the invention is a different remotely disconnectable containment boom. This boom also has a first boom section with a female portion of a quick release boom connector affixed thereto and a second boom section with a male portion of a quick release boom connector affixed thereto. The female portion of the connector includes a pair of spaced parallel walls which extend along a first axis. The female portion further includes a lock element which is pivotably mounted on the exterior of at least one of the walls. An alignment element is also mounted on the exterior of the same wall. The male portion of the connector has a single wall extending along a second axis and further includes a lock engaging element for engagement with the lock element on the female portion of the connector when the male and female portions are operatively engaged, i.e., with the single wall of the male portion inserted between the walls of the female portion. The quick release boom connector further includes a remote activating element passing through the alignment element and attached to the lock element for disengaging the lock element from the lock engagement element from a remote location.
In a preferred embodiment of the invention, the containment boom further includes a stiffening element mounted on the boom sections near the connector.
Another feature of the invention is embodied in a method of remote disconnection of a containment boom. A containment boom having a quick release boom connector with male and female portions affixed thereto and a remote activating element as described above is provided. An operator located remotely from the boom activates the remote activating element to disconnect the boom connector, such as by removing a securing element from channels disposed in each portion, or by disengaging a lock element on the female portion of the connector from a lock engaging element on the male portion of the connector.
Another feature of the invention is embodied in a method of simultaneously transferring two or more combustible liquids between a loading vessel and a receiving vessel, wherein at least one of the vessels is in water and where at least one of the combustible liquids has a low flash point. A remotely disconnectable containment boom according to the invention is placed in the water surrounding the vessels. The combustible liquids are simultaneously transferred from the loading vessel into respective separate compartments of the receiving vessel. If the low flash point liquid spills into the water during the transfer, the remotely disconnectable containment boom is disconnected from a remote location by activation of a remote activating element attached to the connector, thereby opening the boom and permitting the liquid to dissipate away from the vessels. On the other hand, if the high flash point product spills, it will be contained.
These and other features of the invention will be more fully appreciated with reference to the following detailed description which is to be read in conjunction with the attached drawings.